We already have a First Time Mushrooms thread. Me or another mod will merge this thread with that one once you've had the chance to reply
I don't think eating nothing at all is a good idea. For me a big thing is making sure I eat enough when I trip. Not being able to eat and knowing I should be eating something has caused some bad times for me personally.
Good advice here. I fast before my trips usually (but not always) - but I try to time it so that my trip coincides with when it'd be ~3-4 hours since my last meal rather than skipping a meal and going hungry through my trip. I also tend to eat during my trips, usually something light but if I'm comfortable and hungry I'll happily eat a full cooked meal.
Inside or outside is down to personal preference and your mood at the time. Inside you have the advantage of controlled music and a speaker system, TV/films, bed, shower, food, all your usual creature comforts. Outside you have the beauty of the plants and earth around you, the singing of the birds in the trees, the trickling cool water of the stream that you can bathe your feet in.
Personally in my experience I find my best trips are the ones where I do things I wouldn't normally do sober - so if you're the type to spend awful lots of time at home, sitting around on your computer, watching TV etc, go out instead - if you're the type to spend all your time going for walks and exploring nature, try a nice comfortable trip inside.
As for dose, it depends on the level of intensity you want and also the type of mushrooms that you have. Cubensis you'd want to start with 1.5-2g for a lighter to medium trip, and 3-3.5g for a stronger one, while Semilanceata you'll want to lower the dose, taking 1-1.5g or so if you want a lighter trip and no more than 2-2.5g if you want a stronger one.
Hope this answers your questions.